Fix a potential bug where if the read from the QTIODevice returns partial buffers, the the result is not the entire message sent.  Caused due to the overwriting of "buf".  Added an offset and keep it up to date.
Fix a potential bug where if the read from the QTIODevice returns partial
buffers, the the result is not the entire message sent.  Caused due to
the overwriting of "buf".  Added an offset and keep it up to date.

AzureAD/rms-sdk-for-cpp,AzureAD/rms-sdk-for-cpp,AzureAD/rms-sdk-for-cpp